released, either accidently through storms or intentionally by well-meaning pet owners wishing to rerelease their pets to the “wild”. Either way, those actions have had lasting effects on Atlantic ecosystems throughout the Caribbean, with sightings as far north as the waters off of New York and Rhode Island and as far south as Brazil.
They wreak havoc upon the native reef ecosystems with their voracious appetite and their constant breeding. Females are capable of reproducing all year, every two to four days. That’s almost 2 million eggs from a single female each year! Lionfish also seem to be indiscriminate eaters, meaning they aren’t picky when it comes to their prey. We found crabs, juvenile grunts, juvenile wrasses, gobies, and shrimp in the stomach contents of our lionfish. The lionfish’s feeding habits mean trouble for Atlantic reef inhabitants, especially those who were once at the top of the food chain and didn’t have to develop adaptations to avoid predators of their own before lionfish arrived.
Lionfish threaten commercial, recreational, and ecologically important species. That’s a three-tiered attack on our Atlantic reef system. Combine this with the lionfish’s ability to survive and thrive in a wide range of depths, temperatures, salinity and water quality and we have a hugely destructive invasive species that is hard to manage. Put simply, lionfish are ruining ecosystems that are important for animals and human society alike. Studies have shown that a single lionfish can reduce juvenile fish populations in its range by 79% in just five weeks. Not only does this destroy local fisheries and damage the recreational fishing industry, but because lionfish eat the “cleaners” and “grazers” of the reef, species that keep algae growth under control, we also see coral reefs indirectly affected by this invasive species. Coral that conservationists are working so hard to restore and protect because of other factors, like
climate change and ocean acidification, are now under more pressure. It’s like telling a college student during finals that there’s a surprise exam they have no time to prepare for.
Spearfishing is seen as the best lionfish hunting method since this technique prevents the accidental harm of native marine species that belong in the area and need protection. Because they have no natural predators in the Atlantic, these fish haven’t developed a fear of humans. I could literally touch an unsuspecting lionfish victim with the tip of my spear without it even flinching. I meant nothing to them because they didn’t have a reason to fear divers. They just hover in the water, staring at you, until you surprise them with an attack. Missing a lionfish gives that individual the chance to escape and will cause them be a little more cautious of divers and harder to kill in the future.
However, visitors are not permitted to spearfish at the Dry Tortugas National Park, so one would assume that the local lionfish population would be out of control. Except for the summer interns and the park dive team, nobody is consistently monitoring and controlling the population. Yet, in our three months of diving, we only caught 66 lionfish. Sixty-six. That’s less than one lionfish per dive. And most of the sites we searched were targeted sites where there were either reports of lionfish sightings or sites that were excellent lionfish habitats. The randomly chosen sites have very few lionfish, which is a good sign. On average, we found less than one lionfish per hour of searching. We would have starved if our intern pay rate was based on the number of lionfish we caught.
This completely contradicts the findings in other areas of the Florida Keys Marine Sanctuary where lionfish numbers are much higher and more daunting. Single-day lionfish derbies are competitions in which teams of divers and snorkelers work to collect as many lionfish as they can. Derbies conducted by the Reef Environmental Education Foundation (REEF), a non-profit organization committed to ocean conservation, have been known to catch upwards of 600 to 800 lionfish. One 2015 derby actually caught 2,583 lionfish in one day. In contrast, our record was 9 lionfish landed in a single day and even that took a lot of hard work and determination to achieve. Despite our one success, there were periods of several days we would dive and see not a single lionfish.
The obvious question, then, was why were lionfish under control in the Dry Tortugas? As I mentioned, for a majority of the year, nobody at the park is controlling the lionfish population so the lionfish could have grown out of control. No conclusive testing has yet been done, but anecdotal evidence, internet videos, and even the park biological sciences technician’s educated guess find that other, larger predators at the park may have started to feed on the local lionfish population. I will attest that almost every time I shot a lionfish, there was a red grouper lingering, hoping to benefit from my hard work. Because the Dry Tortugas is protected, predator species have the ability to live longer and grow larger. Lionfish sightings in the Dry Tortugas peaked in 2011 and have decreased every year since, possibly due to increased consumption by these unforeseen new predators. This means marine reserves may have yet another benefit for managers and policymakers to cite. If the aforementioned theory proves to be true, the Dry Tortugas may serve to support the idea that the creation of a protected area can help drive down invasive populations such as lionfish by strengthening ecosystems, in turn nurturing larger reef predators that have been declining elsewhere.
I hope to take a first step in supporting the theory that there is a difference in lionfish populations between the protected Dry Tortugas and rest of the less regulated Florida Keys with my graduate project for University of Miami. My initial disgust for slicing open lionfish heads and collecting the tiny, fragile otolith bones soon faded as I took pride in my newfound ability. Collecting the otolith (ear) bones of our catches allowed us to estimate the age of the animals, since those bones have age-rings like those found in a tree trunk. Combined with the data we took on length, weight, and sex, we can then compare the growth of lionfish in the Dry Tortugas National Park to other areas of the Florida Keys. Analyzing this data could potentially show a significant difference in growth between populations in these areas. A population skewed to either extreme (younger and smaller versus larger and older) could support the idea of predatory control of lionfish by predators. We may never be able to completely remove invasive species from their new habitats. With research that supports the ability of ecosystems to adapt and naturally manage invasive populations, however, we could give managers the tools to garner support for new policies that would mitigate damage already done and help affected sites establish a new normal.
What’s more, we need to spread the word that lionfish is perfectly safe to eat. Not only is this a delicious first step to managing this invasive species, but, if presented correctly, consuming lionfish actually becomes an educational experience. What better way to get a person personally connected to a conservation issue than through their stomachs? The biggest misconception is that lionfish are poisonous to diners. They aren’t, they are venomous. Their flesh is not toxic. Poison works through touch, ingestion or inhalation, while venoms are injected directly into a wound. Furthermore, lionfish venom is denatured with heat. In fact, as the venom gets cooked and denatures, the spines become harmless. We’ve seen people use the spines as fancy toothpicks and stylish jewelry. Divers and chefs are the ones at risk, not the people enjoying lionfish pizza, lionfish ceviche, or lionfish tacos.
Effective public education campaigns will help create more demand and an incentive for divers to go out and hunt these fish. And it’s already started. After my internship ended, I saw an unexpected and familiar face staring back at me from the seafood counter at a grocery store in Virginia: a defeated Key West lionfish ready to be eaten by a consumer that has, perhaps unknowingly, just took a first step in helping protect our coral reefs from a predator that is likely to never be fully eradicated.
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